6.3 Skin Barriers (First Line of Defense)

Question 1

Skin

Answer 1

Protects external structures predominantly via thick and tough dead cells
Secretes biochemical agents to inhibit microbial growth

Question 2

Mucous Membranes

Answer 2

protects internal structures via fluid released from living cells
Cells secrete biochemical agents and may be ciliated

Question 3

Clotting

Answer 3

the process by which broken vessels are repaired (prevents bloood loss and limits pathogenic entry)

Question 4

Key components of blood clot

Answer 4

Platelets adhere to one an another to form sticky plug
Fibrin strands for an insoluble mesh at the site of injury

Question 5

Coagulation Cascade

Answer 5

Clotting is initiated via release of clotting factors by platelets (intrinsic or damaged cells (extrinsic)

Question 6

Factors that initiate coagulation cascade (Process of Blood Clotting):

Answer 6

1. Platelets become sticky and form a plug
2. Prothombin is converted into thrombin
3. Thrombin converts fibrinogen into fibrin
4. Fibrin forms a fibrous clot at the plug

Question 7

Thrombosis

Answer 7

the function of a clot inside of a blood vessel (impending blood flow)

Question 8

Process of Thrombosis

Answer 8

Clots form when vessels are damaged by the deposition of cholesterol:
Restricted blood flow increases pressure, damaging the arterial wall
Damages regions are repaired with fibrous tissue, reducing vessel elasticity
This leads to the formation of vessel lesions called atherosclerotic plaques
If a plaque ruptures clotting is triggered to form a thrombus within the vessel